// 已知 base64 字符串，解码并输出用户名与密码
const base64Str = 'emhhbmdzYW46MTIzNDU2';

const decoded = Buffer.from(base64Str, 'base64').toString('utf8');

const [username, password] = decoded.split(':');

console.log(`用户名:${username}  密码:${password}`);



